Washing machine and control method thereof

ABSTRACT

A washing machine operates in stand by for a predetermined time, under the condition that rinse water is not drained during first rinsing out of a plurality of rinsings constituting a rinsing cycle of the washing machine, so as to allow contaminants in the rinse water to settle, performs partial drainage to drain a part of the rinse water is performed, when the predetermined time has elapsed, and performs second rinsing by supplying an amount of water equal to that of the drained rinse water, when the partial drainage has been completed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 2010-0069265, filed on Jul. 17, 2010 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

1. Field

Embodiments of the present disclosure relate to a washing machine.

2. Description of the Related Art

In general, washing machines are apparatuses which remove contaminants from laundry through washing, rinsing, and spin-drying cycles according to a predetermined algorithm, and are divided into a vertical type washing machine (an automatic washing machine) and a drum washing machine. The vertical type washing machine performs washing using rotation of rotating blades and an outer or inner tub (washing tub/spin-drying tub) around a vertical axis. On the other hand, the drum washing machine performs washing using rotation of a drum around a horizontal axis.

These washing machines consume water during washing and rinsing of laundry, and the amount of water that is consumed may be varied according to an amount of the laundry or a contamination degree of the laundry. Consumers in a region, where a sufficient amount of water is available, desire rapid and strong washing regardless of an amount of water consumed, but consumers in a region where an amount of supplied water is insufficient, desire washing with a small amount of water rather than washing speed or efficiency.

SUMMARY

Therefore, it is an aspect of the present disclosure to provide a washing machine and a control method thereof in which an amount of water consumed during a rinsing cycle is greatly reduced so as to achieve water-saving washing.

Additional aspects of the disclosure will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the disclosure.

In accordance with one aspect of the present disclosure, a control method of a washing machine includes operating the washing machine in stand by for a predetermined time, under the condition that rinse water is not drained during first rinsing, so as to allow contaminants in the rinse water to settle, performing partial drainage to drain a part of the rinse water, when the predetermined time has elapsed, and performing second rinsing by supplying an amount of water equal to that of the drained rinse water, when the partial drainage has been completed.

The second rinsing may be the final rinsing out of a plurality of rinsings, and the first rinsing may be rinsing performed just prior to the second rinsing.

Spin-drying may be omitted while the first rinsing and the second rinsing are performed.

The predetermined standby time may be about 2 minutes.

The amount of the drained rinse water may be less than 50% of the total amount of the rinse water.

In accordance with another aspect of the present disclosure, a control method of a washing machine includes judging whether or not a water-saving washing mode is selected, operating the washing machine in stand by for a predetermined time, under the condition that rinse water is not drained during first rinsing, so as to allow contaminants in the rinse water to settle, when it is judged that the water-saving washing mode has been selected, performing partial drainage to drain a part of the rinse water, when the predetermined time has elapsed, and performing second rinsing by supplying an amount of water equal to that of the drained rinse water, when the partial drainage has been completed.

The second rinsing may be the final rinsing out of a plurality of rinsings, and the first rinsing may be rinsing performed just prior to the second rinsing.

Spin-drying may be omitted while the first rinsing and the second rinsing are performed.

The selection of the water-saving washing mode may be achieved by operating a water-saving button provided to switch from a washing mode being performed currently to the water-saving washing mode.

The predetermined standby time may be about 2 minutes.

The amount of the drained rinse water may be less than 50% of the total amount of the rinse water.

In accordance with another aspect of the present disclosure, a control method of a washing machine includes judging whether or not a water-saving washing mode is selected, performing intermediate spin-drying in the water-saving washing mode differently from intermediate spin-drying in other washing modes, when it is judged that the water-saving washing mode has been selected, and performing water-saving rinsing during a rinsing cycle, when it is judged that the water-saving washing mode has been selected.

The water-saving rinsing may include standing by the washing machine for a predetermined time, under the condition that rinse water is not drained during first rinsing, so as to allow contaminants in the rinse water to settle, performing partial drainage to drain a part of the rinse water, when the predetermined time has elapsed, and performing second rinsing by supplying an amount of water equal to that of the drained rinse water, when the partial drainage has been completed.

The second rinsing may be the final rinsing out of a plurality of rinsings, and the first rinsing may be rinsing performed just prior to the second rinsing.

In the performing of the intermediate spin-drying in the water-saving washing mode differently from the intermediate spin-drying in other washing modes, the intermediate spin-drying in the water-saving washing mode may be performed for a longertime than the intermediate spin-drying in other washing modes.

In the performing of intermediate spin-drying in the water-saving washing mode differently from the intermediate spin-drying in other washing modes, a rotational speed RPM of a spin basket during the intermediate spin-drying in the water-saving washing mode may be higher than a rotational speed RPM of the spin basket during the intermediate spin-drying in other washing modes.

Spin-drying may be omitted while the first rinsing and the second rinsing are performed.

An increase in the intermediate spin-drying time in the water-saving washing mode may be determined according to an amount of laundry put into the washing machine.

An increase in the intermediate spin-drying time in the water-saving washing mode may be determined according to a contamination degree of laundry put into the washing machine.

The selection of the water-saving washing mode may be achieved by operating a water-saving button provided to switch from a washing mode being performed currently to the water-saving washing mode.

In accordance with another aspect of the present disclosure, a washing machine includes a tub, a spin basket rotatably installed in the tub, a water supply valve to supply water to the spin basket, a drain valve to drain water in the spin basket, and a control unit to operate the washing machine in stand by for a predetermined time, under the condition that rinse water is not drained during first rinsing, by closing the drain valve so as to allow contaminants in the rinse water to settle, to perform partial drainage to drain a part of the rinse water by opening the drain valve, when the predetermined time has elapsed, and to perform second rinsing by supplying an amount of water equal to that of the drained rinse water by closing the drain valve and opening the water supply valve, when the partial drainage has been completed.

The second rinsing may be the final rinsing out of a plurality of rinsings, and the first rinsing may be rinsing performed just prior to the second rinsing.

The control unit omits spin-drying while the first rinsing and the second rinsing are performed.

The washing machine may further include a water-saving button provided to switch from a washing mode being performed currently to the water-saving washing mode, and the selection of the water-saving washing mode may be achieved by operating the water-saving button.

The predetermined standby time may be about 2 minutes.

The amount of the drained rinse water may be less than 50% of the total amount of the rinse water.

In accordance with another aspect of the present disclosure, a washing machine includes a tub, a spin basket rotatably installed in the tub, a water supply valve to supply water to the spin basket, a drain valve to drain water in the spin basket, and a control unit to judge whether or not a water-saving washing mode is selected, to operate the washing machine in stand by for a predetermined time, under the condition that rinse water is not drained during first rinsing, by closing the drain valve so as to allow contaminants in the rinse water to settle, when it is judged that the water-saving washing mode has been selected, to perform partial drainage to drain a part of the rinse water by opening the drain valve, when the predetermined time has elapsed, and to perform second rinsing by supplying an amount of water equal to that of the drained rinse water by closing the drain valve and opening the water supply valve, when the partial drainage has been completed.

The second rinsing may be the final rinsing out of a plurality of rinsings, and the first rinsing may be rinsing performed just prior to the second rinsing.

The control unit may omit spin-drying while the first rinsing and the second rinsing are performed.

The control unit may set an intermediate spin-drying time in the water-saving washing mode to be longer than an intermediate spin-drying time in other washing modes.

The control unit may set a rotational speed RPM of a spin basket during intermediate spin-drying in the water-saving washing mode to be higher than a rotational speed RPM of the spin basket during intermediate spin-drying in other washing modes.

The washing machine may further include a water-saving button provided to switch from a washing mode being performed currently to the water-saving washing mode, and the selection of the water-saving washing mode may be achieved by operating the water-saving button.

The predetermined standby time may be about 2 minutes.

The amount of the drained rinse water may be less than 50% of the total amount of the rinse water.

In accordance with a further aspect of the present disclosure, a washing machine includes a tub, a spin basket rotatably installed in the tub, a water supply valve to supply water to the spin basket, a drain valve to drain water in the spin basket, and a control unit to judge whether or not a water-saving washing mode is selected, to perform intermediate spin-drying in the water-saving washing mode for a longer time than intermediate spin-drying in other washing modes, when it is judged that the water-saving washing mode has been selected, and to perform water-saving rinsing during a rinsing cycle in the water-saving washing mode, when it is judged that the water-saving washing mode has been selected.

The water-saving rinsing may include standing by the washing machine for a predetermined time, under the condition that rinse water is not drained during first rinsing, so as to allow contaminants in the rinse water to settle, performing partial drainage to drain a part of the rinse water, when the predetermined time has elapsed, and performing second rinsing by supplying an amount of water equal to that of the drained rinse water, when the partial drainage has been completed.

The second rinsing may be the final rinsing out of a plurality of rinsings, and the first rinsing may be rinsing performed just prior to the second rinsing.

The control unit may omit spin-drying while the first rinsing and the second rinsing are performed.

The control unit may determine an increase in the intermediate spin-drying time in the water-saving washing mode according to an amount of laundry put into the washing machine.

The control unit may determine an increase in the intermediate spin-drying time in the water-saving washing mode according to a contamination degree of laundry put into the washing machine.

The washing machine may further include a water-saving button provided to switch from a washing mode being performed currently to the water-saving washing mode, and the selection of the water-saving washing mode may be achieved by operating the water-saving button.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects of the disclosure will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a longitudinal-sectional view of a washing machine in accordance with one embodiment of the present disclosure;

FIG. 2 is a view illustrating a control system of the washing machine of FIG. 1;

FIG. 3 is a flow chart illustrating a control method of a washing machine in accordance with one embodiment of the present disclosure;

FIG. 4 is a flow chart illustrating a rinsing cycle of the control method of FIG. 3 in detail;

FIG. 5 is a flow chart illustrating a control method of a washing machine in accordance with another embodiment of the present disclosure;

FIG. 6 is a flow chart illustrating a rinsing cycle of the control method of FIG. 5 in detail;

FIG. 7 is a flow chart illustrating a control method of a washing machine in accordance with another embodiment of the present disclosure;

FIG. 8 is a flow chart illustrating a control method of a washing machine in accordance with another embodiment of the present disclosure;

FIG. 9 is a view illustrating a control system of a washing machine in accordance with another embodiment of the present disclosure;

FIG. 10 is a flow chart illustrating a control method of a washing machine in accordance with a further embodiment of the present disclosure; and

FIG. 11 is a view illustrating an input unit of the washing machine in accordance with the embodiment of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

FIG. 1 is a longitudinal-sectional view of a washing machine in accordance with one embodiment of the present disclosure. As shown in FIG. 1, the washing machine in accordance with this embodiment includes a tub 11 installed within a main body 10 to contain water (wash water or rinse water), a spin basket 12 rotatably installed in the tub 11 to contain laundry W, and a pulsator 13 rotatably installed in the spin basket 12 and rotated in regular and reverse directions to generate a water current. The washing machine of FIG. 1 is a vertical type washing machine in which the tub 11 and the spin basket 12 are rotated around an almost vertical axis; In general, the vertical type washing machine is controlled such that an amount of laundry is determined by sensing a weight of the laundry and a proper amount of wash water or rinse water suitable for the amount of the laundry is supplied. Here, the amount of the wash water or the rinse water to be supplied means an amount of the wash water or the rinse water reaching a water level enough to submerge most of the laundry. Since a water current generated due to rotation of a pulsator and rotation of a spin basket in the vertical type washing machine needs to be transmitted to the upper portion of the laundry, an amount of wash water or rinse water enough to submerge the laundry is supplied. However, embodiments of the present disclosure may be applied to a drum washing machine.

A motor 14 to generate driving force to rotate the spin basket 12 and the pulsator 13, and a power switch device 15 to simultaneously or selectively transmit the driving force generated by the motor 14 to the spin basket 12 and the pulsator 13 are installed at the outside under the tub 11.

The motor 14 is a direct drive type motor having a speed varying function, and simultaneously or selectively transmits driving force to the spin basket 12 and the pulsator 13 according to ascending and descending operation of the power switch device 15. Instead of the direct drive type motor, the motor 14 may employ a motor to transmit driving force in a belt-pulley type. Here, reference numeral 16 represents a hollow spin-drying shaft connected with the spin basket 12, and reference numeral 17 represent a washing shaft installed in a hollow of the spin-drying shaft 16 so as to be connected with the pulsator 13 through the spin-drying shaft 16.

A water level detection unit 18 to sense a frequency varied according to a water level so as to sense a level (amount) of water in the tub 11 is installed at the inside of the lower portion of the tub 11. The water level detection unit 18 senses a level of water contained in the spin basket 12, thereby allowing a desired amount of wash water or rinse water to be supplied or a desired amount of water (for example, a part of the amount of water contained in the tub 11) to be drained. Further, a contamination degree detection unit 106 to detect of a contamination degree of water in the tub 11 is installed at the inside of the lower portion of the tub 11. Further, a drain valve 102 and a drain pipe 104 to drain the water in the tub 11 to the outside of the washing machine are installed under the tub 11. All or a part of the amount of water in the tub 11 is drained to the outside of the washing machine by controlling opening/closing of the drain valve 102. A water supply valve 19 to supply water to the tub 11 is installed above the tub 11.

FIG. 2 is a view illustrating a control system of the washing machine of FIG. 1. As shown in FIG. 2, an input unit 204, the contamination degree detection unit 106, and the water level detection unit 18 are communicably connected to an input side of a control unit 202 to control the overall operation of the washing machine, and the motor 14, the water supply valve 19, the drain valve 102, and a display unit 206 are drivably connected to an output side of the control unit 202. The input unit 204 serves to allow a user to select various other conditions relating to washing (for example, a water level of wash water or rinse water, the number of times that spin-drying is performed, a spin-drying speed, the number of times that rinsing is performed, etc.) as well as a washing mode, and to receive and transmit the factors selected by the user to the control unit 202. The user may select a desired washing mode (for example, a water-saving washing mode or a general washing mode) and washing conditions through the manipulation of the input unit 204. The display unit 206 serves to display an operating state of the washing machine, i.e., to display the currently selected washing mode and a proceeding state (for example, an elapsed time). Further, during a standby time when contaminants contained in rinse water settle in the water-saving washing mode in accordance with the embodiment of the present disclosure, the display unit 206 displays that the standby time is a standby time for water saving so as to prevent the user from incorrectly believing that the washing machine has malfunctioned. Further, the display unit 206 may display the remaining standby time. The contamination degree detection unit 106, the water level detection unit 18, the motor 14, the water supply valve 19, and the drain valve 102 have been already described in FIG. 1.

FIG. 3 is a flow chart illustrating a control method of a washing machine in accordance with one embodiment of the present disclosure. The control method of FIG. 3 is performed when a user selects the water-saving washing mode, and water-saving is carried out during a rinsing cycle 304 out of a washing cycle 302, the rinsing cycle 304, and a spin-drying cycle 306.

During the washing cycle 302, water and detergent are supplied to the inside of the tub 11, and the spin-basket 12, in which laundry is placed, is rotated, thereby performing washing of the laundry.

During the rinsing cycle 304, rinsing may be performed twice. The number of times that the rinsing is performed during the rinsing cycle 304 may be varied according to an amount or a contamination degree of the laundry and the washing mode selected by the user. During the rinsing cycle 304 of FIG. 3, first rinsing 308 and second rinsing 310 are sequentially performed, and the first rinsing 308 is water-saving rinsing.

During the spin-drying cycle 306, moisture is removed from the laundry after the washing and rinsing cycles 302 and 304. Here, moisture is removed from the laundry by means of centrifugal force generated by rotating the spin basket 12 at a high speed.

FIG. 4 is a flow chart illustrating the rinsing cycle of the control method of FIG. 3 in detail. As shown in FIG. 4, during the first rinsing 308 which is water-saving rinsing, rinse water is supplied (operation 402), rinsing is performed (operation 404), and then the spin-basket 12 in a stopped state stands by for a predetermined time without drainage (operation 406). Thereafter, when the predetermined time has elapsed, only a part of the supplied rinse water is drained (partial drainage, operation 408). Here, standby means that a state in which the spin basket 12 and the pulsator 13 are not rotated so as not to drain the rinse water is maintained for the predetermined time. Such standby serves to allow contaminants contained in the rinse water to settle to the bottom of the spin basket 12. When a part of the rinse water is drained under the condition that the contaminants contained in the rinse water settle to the bottom of the spin basket 12, a considerable amount of the contaminants on the bottom of the spin basket 12 is discharged and thus only the rinse water from which the considerable amount of the contaminants has been removed remains in the spin basket 12. If the drain pipe 104 is located under the tub 11, as shown in FIG. 1, the contaminants are very effectively discharged due to partial drainage after settlement.

During the second rinsing (final rinsing) 310, an amount of water equal to that of the drained rinse water during the first rinsing 308 is supplied (operation 410). Since only the rinse water from which the considerable amount of the contaminants has been removed remains in the spin basket 12 after the partial drainage of the first rinsing 308, if only a deficit of water (for example, the amount of water equal to that of the drained rinse water) is supplied and then rinsing is performed again, an amount of water equal to that of the remaining amount of the rinse water during the first rinsing 308 is saved. Such water saving is achieved by holding the spin basket 12 without drainage for the predetermined time so as to allow the contaminants to settle during the first rinsing 307. When the water supply (operation 410) has been completed during the first rinsing 310, rinsing is performed (operation 412), and complete drainage is performed (operation 414). Thereby, the rinsing cycle 304 is completed. The complete drainage means that all amount of water in the tub 11 is simultaneously drained.

As shown in FIG. 4, spin-drying between the rinsing for water saving (i.e., the first rinsing 308) and the final rinsing (i.e., the second rinsing 310) is omitted. That is, complete drainage is not performed but partial drainage is performed during the first rinsing 308, and thus spin-drying is not necessary.

The predetermined standby time of the first rinsing 308 which is water-saving rinsing may be about 2 minutes. However, the standby time may be varied in proportion to the amount of the laundry or the contamination degree of the rinse water. That is, if the amount of the laundry is large or the contamination degree of the rinse water is high, the standby time is extended, and if the amount of the laundry is small or the contamination degree of the rinse water is low, the standby time is shortened.

Further, the amount of the drained part of the rinse water during the first rinsing 308 may not exceed 50% of the total amount of the supplied rinse water, and may be as small as possible, in order to achieve water saving. When the amount of the drained part of the rinse water increases, a water-saving effect decreases. On the other hand, the amount of the drained part of the rinse water may be varied in proportion to the contamination degree of the rinse water (if both the water level detection unit and the contamination degree detection unit are provided). That is, the higher the contamination degree of the rinse water, the greater is the amount of the drained part of the rinse water, and the lower the contamination degree of the rinse water, the smaller is the amount of the drained part of the rinse water. If the contamination degree detection unit is not provided, the amount of the drained part of the rinse water may be varied in proportion to the amount of the laundry.

FIG. 5 is a flow chart illustrating a control method of a washing machine in accordance with another embodiment of the present disclosure. As shown in FIG. 5, if during a rinsing cycle 504, rinsing is performed four times or more, water-saving rinsing is performed about twice at the final stage of the rinsing cycle 504.

During a washing cycle 502, water and detergent are supplied to the inside of the tub 11, and the spin-basket 12, in which laundry is placed, is rotated, thereby performing washing of the laundry. During the washing cycle 502, spin-drying is performed a predetermined number of times.

During the rinsing cycle 504, rinsing is performed plural times (for example, four times). The number of times that the rinsing is performed during the rinsing cycle 504 may be varied according to an amount or a contamination degree of the laundry and a washing mode selected by a user. During the rinsing cycle 504 of FIG. 5, first rinsing 508, second rinsing 510, third rinsing 512, and fourth rinsing 514 are sequentially performed, and the second rinsing 510 and the third rinsing 512 are water-saving rinsing. That is, the second rinsing 510 and the third rinsing 512 of FIG. 5, which are the water-saving rinsing, correspond to the first rinsing 308 of FIG. 3, and the fourth rinsing 514 of FIG. 5, which is the final rinsing, corresponds to the second rinsing 310 of FIG. 3.

During a spin-drying cycle 506, moisture is removed from the laundry after the washing and rinsing cycles 502 and 504. Here, moisture is removed from the laundry by means of centrifugal force generated by rotating the spin basket 12 at a high speed.

FIG. 6 is a flow chart illustrating the rinsing cycle of the control method of FIG. 5 in detail. As shown in FIG. 6, during the first rinsing 510 which is no water-saving rinsing, water supply, rinsing, complete drainage, and spin-drying are sequentially performed. The complete drainage means that all amount of water in the tub 11 is simultaneously drained once. During the second rinsing 512, rinse water is supplied (operation 602), rinsing is performed (operation 604), and then the spin-basket 12 in a stopped state stands by for a predetermined time without drainage (operation 606). Thereafter, when the predetermined time has elapsed, only a part of the supplied rinse water is drained (partial drainage, operation 608). Here, standby means that a state in which the spin basket 12 and the pulsator 13 are not rotated so as not to drain the rinse water is maintained for the predetermined time. Such standby serves to allow contaminants contained in the rinse water to settle to the bottom of the spin basket 12. When a part of the rinse water is drained under the condition that the contaminants contained in the rinse water settle to the bottom of the spin basket 12, a considerable amount of the contaminants on the bottom of the spin basket 12 is discharged and thus only the rinse water from which the considerable amount of the contaminants has been removed remains in the spin basket 12.

During the third rinsing 514, an amount of water equal to that of the drained rinse water during the second rinsing 512 is supplied (operation 610). Since only the rinse water from which the considerable amount of the contaminants has been removed remains in the spin basket 12, if only a deficit of water (for example, the amount of water equal to that of the drained rinse water) is supplied and then rinsing is performed again, an amount of water equal to that of the remaining amount of the rinse water during the second rinsing 512 is saved. Such water saving is achieved by holding the spin basket 12 without drainage for the predetermined time so as to allow the contaminants to settle during the second rinsing 512. When the water supply (operation 610) has been completed, rinsing is performed (operation 612), and then the spin-basket 12 in a stopped state stands by for a predetermined time without drainage (operation 614). Thereafter, when the predetermined time has elapsed, only a part of the supplied rinse water is drained (partial drainage, operation 616). During the fourth rinsing 516, an amount of water equal to that of the drained rinse water during the third rinsing 514 is supplied (operation 618). Since only the rinse water from which the considerable amount of the contaminants has been removed remains in the spin basket 12 under the condition that the partial rinsing has been completed during the third rinsing 514, if only a deficit of water (for example, the amount of water equal to that of the drained rinse water) is supplied and then rinsing is performed again, an amount of water equal to that of the remaining amount of the rinse water during the third rinsing 514 is saved. Such water saving is achieved by holding the spin basket 12 without drainage for the predetermined time so as to allow the contaminants to settle during the third rinsing 514. When the water supply (operation 618) has been completed during the fourth rinsing 516, rinsing is performed (operation 620), and complete drainage is performed (operation 622). Thereby, the rinsing cycle 504 is completed. The complete drainage means that all amount of water in the tub 11 is simultaneously drained.

The predetermined standby time of each of the second rinsing 512 and the third rinsing 514 which are water-saving rinsing may be about 2 minutes. However, the standby time may be varied in proportion to the amount of the laundry or the contamination degree of the rinse water. That is, if the amount of the laundry is large or the contamination degree of the rinse water is high, the standby time is extended, and if the amount of the laundry is small or the contamination degree of the rinse water is low, the standby time is shortened.

Further, the amount of the drained part of the rinse water during each of the second rinsing 512 and the third rinsing 514 may not exceed 50% of the total amount of the supplied rinse water, and may be as small as possible, in order to achieve water saving. When the amount of the drained part of the rinse water increases, a water-saving effect decreases. On the other hand, the amount of the drained part of the rinse water may be varied in proportion to the contamination degree of the rinse water (if both the water level detection unit and the contamination degree detection unit are provided). That is, the higher the contamination degree of the rinse water, the greater is the amount of the drained part of the rinse water, and the lower the contamination degree of the rinse water, the smaller is the amount of the drained part of the rinse water. If the contamination degree detection unit is not provided, the amount of the drained part of the rinse water may be varied in proportion to the amount of the laundry.

FIG. 7 is a flow chart illustrating a control method of a washing machine in accordance with another embodiment of the present disclosure. As shown in FIG. 7, the washing machine is turned on (operation 702), and then the control unit 202 receives a washing mode selected by a user through the input unit 204 (operation 704). If the washing mode selected by the user is a water-saving washing mode (yes in operation 706), the water-saving washing operation in accordance with one of the embodiments of the present disclosure, as shown in FIGS. 3 to 6, is performed (operation 708). On the other hand, if the washing mode selected by the user is not the water-saving washing mode (no in operation 706), a general washing operation, as opposed to the washing-saving operation in accordance with one of the embodiments of the present disclosure, as shown in FIGS. 3 to 6, is performed (operation 710). By performing the water-saving washing operation only if needed in response to the washing mode selected by the user, instead of all cases, the control method may properly cope with a case in which water saving is more required and a case in which a short washing time is more required.

FIG. 8 is a flow chart illustrating a control method of a washing machine in accordance with another embodiment of the present disclosure. As shown in FIG. 8, the washing machine is turned on (operation 802), and then the control unit 202 receives a washing mode selected by a user through the input unit 204 (operation 804). If the washing mode selected by the user is a water-saving washing mode (yes in operation 806), a water-saving washing operation similar to that in accordance with one of the embodiments of the present disclosure, as shown in FIGS. 3 to 6, is performed (operation 808). On the other hand, if the washing mode selected by the user is not the water-saving washing mode (no in operation 806), a general washing operation, as opposed to the washing-saving operation, is performed (operation 810).

The control method of FIG. 8 differs from the control methods in accordance with the former embodiments in that an intermediate spin-drying time during a washing cycle 812 in the water-saving washing mode is longer than an intermediate spin-drying time during a washing cycle in the general washing mode. Here, the intermediate spin-drying means spin-drying performed during the washing cycle 812 so as to remove contaminated wash water from laundry. That is, the washing cycle 812 is achieved in a procedure of water supply 812 a, washing 812 b, drainage 812 c, and spin-drying 812 d, and the spin-drying 812 d during the washing cycle 812 is referred to as intermediate spin-drying. Further, spin-drying performed during the rinsing cycle to rinse laundry, washing of which has been completed, may also be defined as intermediate spin-drying. Detection of an amount of laundry is performed prior to the washing cycle. Such laundry amount detection serves to judge optimum operating conditions (time, water amount, etc.) according to the amount of the laundry. These washing mode operating conditions may be automatically set by judgment of the control unit 202 according to a result of the laundry amount detection, or may be directly set by user input. After the intermediate spin-drying, wash water may be resupplied and then washing may be repeated. The reason why the time of the intermediate spin-drying performed during the washing cycle 812 in the water-saving washing mode is increased to be longer than that of the intermediate spin-drying time during the washing cycle in the general washing mode is as follows. During the rinsing cycle 814 of FIG. 8, water-saving rinsing is performed, and thus spin-drying is omitted, as described above with reference to FIGS. 3 to 6. Therefore, a rinsing effect may be reduced due to omission of spin-drying during the rinsing cycle 814, and thus in order to compensate for the reduced rinsing effect, a spin-drying time during the washing cycle 812 is more increased (compared with the general washing mode). When the spin-drying time during the washing cycle 812 is more increased, a larger amount of moisture containing contaminants is discharged, and thus although spin-drying is insufficiently performed during the rinsing cycle 814, a sufficient rinsing effect may be obtained throughout the whole water-saving washing mode.

As another method to improve the rinsing effect, a rotational speed RPM of the spin basket 12 during spin-drying may be more increased instead of increasing the spin-drying time. When the rotational speed RPM of the spin basket 12 during spin-drying is more increased, a desired improved rinsing effect may be obtained without increasing the washing time. In order to obtain the improved rinsing effect, both an increase in the spin-drying time and an increase in the rotational speed RPM of the spin basket 12 may be applied.

Such an increase in the spin-drying time or an increase in the rotational speed RPM of the spin basket 12 may be applied to intermediate spin-drying during the rinsing cycle as well as to intermediate spin-drying during the washing cycle, thereby improving the rinsing effect. For example, in the embodiment of FIG. 6, the rinsing effect may be improved by increasing the spin-drying time or the rotational speed RPM of the spin basket 12 in spin-drying performed during the first rinsing.

Further, water-saving washing is not performed in all washing modes, but is performed only if needed in response to the washing mode selected by the user, the control method may properly cope with a case in which water saving is more required and a case in which a short washing time is more required.

FIG. 9 is a view illustrating a control system of a washing machine in accordance with another embodiment of the present disclosure. As shown in FIG. 9, an input unit 904, the contamination degree detection unit 106, and the water level detection unit 18 are communicably connected to an input side of a control unit 902 to control the overall operation of the washing machine, and the motor 14, the water supply valve 19, the drain valve 102, and a display unit 906 are drivably connected to an output side of the control unit 902. The input unit 904 serves to allow a user to directly select other various conditions relating to washing (for example, a water level of wash water or rinse water, the number of times that spin-drying is performed, a spin-drying speed, the number of times that rinsing is performed, etc.) as well as a washing mode, and to receive and transmit the factors selected by the user to the control unit 902. Further, a water-saving button 904 a is provided on the input unit 904. The water-saving button 904 a allows the user to easily and rapidly switch from the current washing mode to the water-saving washing mode. In more detail, if the washing machine is operated in a washing mode other than the water-saving washing mode, when the user operates the water-saving button 904 a, the current washing mode is switched to the water-saving washing mode, and if a process being subject to the water-saving washing is present among remaining processes, which are not performed in the former washing mode, only the corresponding process is performed in the water-saving washing mode. The display unit 906 serves to display an operating state of the washing machine, i.e., to display the currently selected washing mode and a proceeding state (for example, an elapsed time). Further, during a standby time when contaminants contained in rinse water settle in the water-saving washing mode in accordance with the embodiment of the present disclosure, the display unit 906 displays that the standby time is a standby time for water saving so as to prevent the user from incorrectly believing that the washing machine has malfunctioned. Further, the display unit 906 may display the remaining standby time. The contamination degree detection unit 106, the water level detection unit 18, the motor 14, the water supply valve 19, and the drain valve 102 have been already described in FIG. 1.

FIG. 10 is a flow chart illustrating a control method of a washing machine in accordance with a further embodiment of the present disclosure. As shown in FIG. 10, the washing machine is turned on (operation 1002), and then the control unit 902 receives a general washing mode selected by a user through the input unit 904 (operation 1004). If the general washing mode selected by the user is one example of a non-water-saving washing mode. The control unit 902 controls the washing machine so as to start the operation of the washing machine in the general washing mode (operation 1006). If water-saving is selected by operating the water-saving button 904 during the general washing mode (yes in operation 1008), the control unit 902 switches from the current washing mode of the washing machine to the water-saving washing mode (operation 1010), and performs the remaining processes, which are not performed in the former washing mode (i.e., the general washing mode), in the water-saving washing mode (operation 1012). Only if a process being subject to the water-saving washing is present among the remaining processes, which are not performed in the former washing mode, the control unit 902 performs the corresponding process in the water-saving washing mode. If water-saving is not selected by operating the water-saving button 904 during the general washing mode (no in operation 1008), the control unit 902 continuously operates the washing machine in the general washing mode (operation 1014).

FIG. 11 is a view illustrating the input unit of the washing machine in accordance with the embodiment of the present disclosure. As shown in FIG. 11, the input unit 904 is provided on the upper end of the external surface of the washing machine, thereby helping a user to operate the washing machine. The water-saving button 904 a, as shown in FIG. 9, is provided on the input unit 904, and the user easily selects the water-saving washing mode through the simple operation of the water-saving button 904 a.

As is apparent from the above description, a washing machine and a control method thereof in accordance with one embodiment of the present disclosure greatly reduce an amount of water consumed during a rinsing cycle so as to achieve water-saving washing.

Although a few embodiments of the present disclosure have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. 

1. A control method of a washing machine comprising: operating the washing machine in stand by for a predetermined time, under the condition that rinse water is not drained during first rinsing, so as to allow contaminants in the rinse water to settle; performing partial drainage to drain a part of the rinse water, when the predetermined time has elapsed; and performing second rinsing by supplying an amount of water equal to that of the drained rinse water, when the partial drainage has been completed.
 2. The control method according to claim 1, wherein the second rinsing is the final rinsing out of a plurality of rinsings, and the first rinsing is rinsing performed just prior to the second rinsing.
 3. The control method according to claim 1, wherein spin-drying is omitted while the first rinsing and the second rinsing are performed.
 4. The control method according to claim 1, wherein the predetermined standby time is about 2 minutes.
 5. The control method according to claim 1, wherein the amount of the drained rinse water is less than 50% of the total amount of the rinse water.
 6. A control method of a washing machine comprising: judging whether or not a water-saving washing mode is selected; operating the washing machine in stand by for a predetermined time, under the condition that rinse water is not drained during first rinsing, so as to allow contaminants in the rinse water to settle, when it is judged that the water-saving washing mode has been selected; performing partial drainage to drain a part of the rinse water, when the predetermined time has elapsed; and performing second rinsing by supplying an amount of water equal to that of the drained rinse water, when the partial drainage has been completed.
 7. The control method according to claim 6, wherein the second rinsing is the final rinsing out of a plurality of rinsings, and the first rinsing is rinsing performed immediately prior to the second rinsing.
 8. The control method according to claim 6, wherein spin-drying is omitted while the first rinsing and the second rinsing are performed.
 9. The control method according to claim 6, wherein the selection of the water-saving washing mode is achieved by operating a water-saving button provided to switch from a washing mode being performed currently to the water-saving washing mode.
 10. The control method according to claim 6, wherein the predetermined standby time is about 2 minutes.
 11. The control method according to claim 6, wherein the amount of the drained rinse water is less than 50% of the total amount of the rinse water.
 12. A control method of a washing machine comprising: judging whether or not a water-saving washing mode is selected; performing intermediate spin-drying in the water-saving washing mode differently from intermediate spin-drying in other washing modes, when it is judged that the water-saving washing mode has been selected; and performing water-saving rinsing during a rinsing cycle, when it is judged that the water-saving washing mode has been selected.
 13. The control method according to claim 12, wherein the water-saving rinsing includes: operating the washing machine in stand by for a predetermined time, under the condition that rinse water is not drained during first rinsing, so as to allow contaminants in the rinse water to settle; performing partial drainage to drain a part of the rinse water, when the predetermined time has elapsed; and performing second rinsing by supplying an amount of water equal to that of the drained rinse water, when the partial drainage has been completed.
 14. The control method according to claim 12, wherein the second rinsing is the final rinsing out of a plurality of rinsings, and the first rinsing is rinsing performed just prior to the second rinsing.
 15. The control method according to claim 12, wherein in the performing of the intermediate spin-drying in the water-saving washing mode differently from the intermediate spin-drying in other washing modes, the intermediate spin-drying in the water-saving washing mode is performed for a longer time than the intermediate spin-drying in other washing modes.
 16. The control method according to claim 12, wherein in the performing of intermediate spin-drying in the water-saving washing mode differently from the intermediate spin-drying in other washing modes, a rotational speed RPM of a spin basket during the intermediate spin-drying in the water-saving washing mode is higher than a rotational speed RPM of the spin basket during the intermediate spin-drying in other washing modes.
 17. The control method according to claim 12, wherein spin-drying is omitted while the first rinsing and the second rinsing are performed.
 18. The control method according to claim 15, wherein an increase in the intermediate spin-drying time in the water-saving washing mode is determined according to an amount of laundry put into the washing machine.
 19. The control method according to claim 15, wherein an increase in the intermediate spin-drying time in the water-saving washing mode is determined according to a contamination degree of laundry put into the washing machine.
 20. The control method according to claim 12, wherein the selection of the water-saving washing mode is achieved by operating a water-saving button provided to switch from a washing mode being performed currently to the water-saving washing mode.
 21. A washing machine comprising: a tub; a spin basket rotatably installed in the tub; a water supply valve to supply water to the spin basket; a drain valve to drain water in the spin basket; and a control unit to operate the washing machine in stand by for a predetermined time, under the condition that rinse water is not drained during first rinsing, by closing the drain valve so as to allow contaminants in the rinse water to settle, to perform partial drainage to drain a part of the rinse water by opening the drain valve, when the predetermined time has elapsed, and to perform second rinsing by supplying an amount of water equal to that of the drained rinse water by closing the drain valve and opening the water supply valve, when the partial drainage has been completed.
 22. The washing machine according to claim 21, wherein the second rinsing is the final rinsing out of a plurality of rinsings, and the first rinsing is rinsing performed just prior to the second rinsing.
 23. The washing machine according to claim 21, wherein the control unit omits spin-drying while the first rinsing and the second rinsing are performed.
 24. The washing machine according to claim 21, further comprising a water-saving button provided to switch from a washing mode being performed currently to the water-saving washing mode, wherein the selection of the water-saving washing mode is achieved by operating the water-saving button.
 25. The washing machine according to claim 21, wherein the predetermined standby time is about 2 minutes.
 26. The washing machine according to claim 21, wherein the amount of the drained rinse water is less than 50% of the total amount of the rinse water.
 27. A washing machine comprising: a tub; a spin basket rotatably installed in the tub; a water supply valve to supply water to the spin basket; a drain valve to drain water in the spin basket; and a control unit to judge whether or not a water-saving washing mode is selected, to operate the washing machine in stand by for a predetermined time, under the condition that rinse water is not drained during first rinsing, by closing the drain valve so as to allow contaminants in the rinse water to settle, when it is judged that the water-saving washing mode has been selected, to perform partial drainage to drain a part of the rinse water by opening the drain valve, when the predetermined time has elapsed, and to perform second rinsing by supplying an amount of water equal to that of the drained rinse water by closing the drain valve and opening the water supply valve, when the partial drainage has been completed.
 28. The washing machine according to claim 27, wherein the second rinsing is the final rinsing out of a plurality of rinsings, and the first rinsing is rinsing performed just prior to the second rinsing.
 29. The washing machine according to claim 27, wherein the control unit omits spin-drying while the first rinsing and the second rinsing are performed.
 30. The washing machine according to claim 27, wherein the control unit sets an intermediate spin-drying time in the water-saving washing mode to be longer than an intermediate spin-drying time in other washing modes.
 31. The washing machine according to claim 27, wherein the control unit sets a rotational speed RPM of a spin basket during intermediate spin-drying in the water-saving washing mode to be higher than a rotational speed RPM of the spin basket during intermediate spin-drying in other washing modes.
 32. The washing machine according to claim 27, further comprising a water-saving button provided to switch from a washing mode being performed currently to the water-saving washing mode, wherein the selection of the water-saving washing mode is achieved by operating the water-saving button.
 33. The washing machine according to claim 27, wherein the predetermined standby time is about 2 minutes.
 34. The washing machine according to claim 27, wherein the amount of the drained rinse water is less than 50% of the total amount of the rinse water.
 35. A washing machine comprising: a tub; a spin basket rotatably installed in the tub; a water supply valve to supply water to the spin basket; a drain valve to drain water in the spin basket; and a control unit to judge whether or not a water-saving washing mode is selected, to perform intermediate spin-drying in the water-saving washing mode for a longer time than intermediate spin-drying in other washing modes, when it is judged that the water-saving washing mode has been selected, and to perform water-saving rinsing during a rinsing cycle in the water-sawing washing mode, when it is judged that the water-saving washing mode has been selected.
 36. The washing machine according to claim 35, wherein the water-saving rinsing includes: operating the washing machine in stand by for a predetermined time, under the condition that rinse water is not drained during first rinsing, so as to allow contaminants in the rinse water to settle; performing partial drainage to drain a part of the rinse water, when the predetermined time has elapsed; and performing second rinsing by supplying an amount of water equal to that of the drained rinse water, when the partial drainage has been completed.
 37. The washing machine according to claim 35, wherein the second rinsing is the final rinsing out of a plurality of rinsings, and the first rinsing is rinsing performed just prior to the second rinsing.
 38. The washing machine according to claim 35, wherein the control unit omits spin-drying while the first rinsing and the second rinsing are performed.
 39. The washing machine according to claim 35, wherein the control unit determines an increase in the intermediate spin-drying time in the water-saving washing mode according to an amount of laundry put into the washing machine.
 40. The washing machine according to claim 35, wherein the control unit determines an increase in the intermediate spin-drying time in the water-saving washing mode according to a contamination degree of laundry put into the washing machine.
 41. The washing machine according to claim 35, further comprising a water-saving button provided to switch from a washing mode being performed currently to the water-saving washing mode, wherein the selection of the water-saving washing mode is achieved by operating the water-saving button. 